Device for withdrawing mine-props and for like purposes



W. TEMPLE DEVICE FOR WITHDRAWING MINE PROPS AND FOR LIKE PURPOSES.

, APPLICATION FILED on. 29. I921.

1,399,279, Patented Dec. 6,1921.

PATENT OFFICE.

WILLIAM TEMPLE, OF BEDLINGTON, ENGLAND.

DEVICE FOR WITHDRAWING MINE-PROPS AND FOR LIKE PURPOSES.

Specification of Letters Patent.

Patented Dec. 6, 1921.

Application fi1ed0ctoben29, 1921. Serial No. 511,499.

To all whom "it may concern:

Be it known that I, WILLIAM'TEMPLE, a subject of the King of Great Britain and Ireland, residing at Bedlington, in the county of Northumberland, England, have invented new and useful Improvements in Devices for Withdrawing Mine-Props and for like Purposes (for which I have filed application in Great Britain under No. 16,524, June 18, 1920,) of which the follow ing is a specification.

This invention relates to devices for withdrawing mine props and for like purposes, wherein a slotted block is mounted on a toothed bar and provided with a spring pawl adapted to coact with the teeth of the, bar, said block being connected by a pivoted link to an operating lever whose fulcrum pin is adapted to engage the teeth of the bar so that, when one endof the chain secured around the member to be withdrawn is attached to the block and the rear end of the bar is anchored, the block can be traveled along the bar to pull in the chain and so withdraw the member by engaging the fulcrum pin of the operating lever with successive teeth of the bar and rocking the lever thereabout, the pawl preventing the return of the block.

The object of the present invention is to provide an improved construction.

According to this invention the bar is provided with two sets of teeth, one set as usual for the fulcrum pin of the operating lever and the other for the spring pawl on the block, the pitch of the teeth for the pawl being a fractional part of the pitch of the teeth for the fulcrum pin. In this way each stroke of the operating lever will carry the pawl a plurality of teeth so that, when the strain is heavy, the operator can work less than a stroke at a time. A catch device is also provided on the bar to automatically prevent return travel.

I will fully describe my invention with reference to the accompanying drawings wherein Figure 1 is a side elevation of one construction of prop -withdrawing device embodying my invention; Figs. 2 and 3 are a part sectional elevation and part plan respectively to a larger scale; Fig. 4: is an underside plan of the catch device; and Fig. 5 is a part similar view to Fig. 1 illustrating a modified manner of usingthe apparatus.

Referring to the drawings, in the device therein illustrated, ais the slotted block and b the toothed bar. The block is connected by a pivoted link 0 to one end of an operating lever d whose fulcrum pin 6 engages and coacts with the teeth 7 of the bar so that, by rocking the lever, the block can be traveled along the bar to the right. The chain 9 is secured around the prop h'to be withdrawn and attached to the block a by a removable pin j passing througha link of the chain. is is an anchoring'chain attached to the rear end of the bar I) and secured around a fixed prop m.

The bar I; is provided with a set of teeth a in addition to the teeth fwith which the fulcrum pin 6 of the lever d coacts, said additional set of teeth being conveniently provided along the top of the bar. The teeth a are engaged by the spring pawl p in the block a whlch automatically prevents the return of the block when it is traveled by the lever cl. The pitch of the teeth a is half of, the pitch of the teeth f so that each stroke of the lever d carries the pawl two teeth, which, when the strain is heavy, allows the operator to work half a stroke at a time.

The front end of the bar I) is provided with a catch device for automatically preventing return travel of the chain 9 and for temporarily holding said chain when the block 0; reaches the rear end of the bar I) while the end of the chain 9 is released from said block and the block is returned to initial position at the front end of the bar 5 when another link of the chain 9 correspondingly nearer to the prop h can be attached to the block a by the pin j, the block being then ready for a second pull. The catch device comprises, as shown in Figs. 1 and 4, a block 9 fixed on the front end of the bar b by a pin a", said block carrying two oppositely-disposed springpressed pivoted pawls 8 arranged so as to allow travel of the chain 9 in the pulling direction (indicated by the arrow in Fig. 1) through the gate t of the block 9 but to prevent return travel of the chain. The pawls clear the vertical links of the chain 9 but engage the horizontal links. The ends a of the cheeks o of the block 9 limit the backward movement of the pawls. The gate also serves to guide the chain 9 and insure that it and the bar 5 will be always parallel to the direction of the pull.

While my improved device is specially applicable for withdrawing props and ,girding, the lever d wi 1 preferably be disposed so that it embraces the bar I), the end ofthe lever being forked for a length suflicient to permit of this. The link 0 is connected to the pin e and the pin w (which previously connected the link to the lever) becomes the fulcrum pin. When the lever is thus arran ed, the downward stroke is the working stro e.

What I claim as m invention and desire to secure by Letters atent is 1. In a device for withdrawing mine props and for like purposes, the combination of a bar, teeth on two sides thereof the pitch of the teeth on one side being a fractional part of the pitch of the teethon the other side, a slotted block mounted on said bar, a spring pawl carried bysaid block engaging the closer-spaced teeth of said bar, an operating lever having a fulcrum pin engaging the wider-spaced teeth of said bar, a pivoted link connecting. said operating lever to said block, a chain ,for attaching said block to the member tobe withdrawn and means for anchoring the rear end of said bar.

2. In a device for Withdrawing -mine props and for like purposes, the combination of a bar, teeth on two sides thereof the pitch of the teeth on one side being a said bar, an operating lever having a fulcrum pin engaging the wider-spaced teeth of said bar, a pivotedlink connecting said operating lever to said block, a chain for attaching said block to the member to be withdrawn, and means for automatically preventing return travel of said chain when it is released from the block."

3. In a device for withdrawing mine props and for like purposes,'the combina- N tion ofa bar, teeth on two sides-thereof the pitch of the teeth on one side being'a'fractional part of thepitch of theteeth on the other side, a slotted block mounted on'said bar, a spring pawl carriedjby said'block engaging the closer-spaced teeth of said bar, an operating lever having a fulcrum pin engagingthe wider-spaced teeth'of said bar,

a pivoted link connecting said operating R lever to said block, a chain for attaching said block to the member to be withdrawn, a catch block fixed 0n the front end of said bar, and two. oppositely-disposed springpressed pivoted pawls mounted on said catch block allowing travel of said chain in the pulling direction but preventing return travel of said chain.

In testimony whereof I name to this specification.

WILLIAM TEMPLE.

have signed my 

